Lanthanum hydroxide

(Redirected from Lanthanum(III) hydroxide)

Lanthanum hydroxide is La(OH)
3
, a hydroxide of the rare-earth element lanthanum.

Lanthanum(III) hydroxide

__ La3+     __ OH
Names
IUPAC name
Lanthanum(III) hydroxide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.034.994 Edit this at Wikidata
EC Number
  • 238-510-2
UNII
  • InChI=1S/La.3H2O/h;3*1H2
    Key: YXEUGTSPQFTXTR-UHFFFAOYSA-K
  • [OH-].[OH-].[OH-].[La+3]
Properties
La(OH)3
Molar mass 189.93 g/mol
Ksp= 2.00·10−21
Structure
hexagonal
P63/m, No. 176
a = 6.547 Å, c = 3.854 Å
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Irritant
GHS labelling:[1]
GHS05: Corrosive
Danger
H314
P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability (red): no hazard codeInstability (yellow): no hazard codeSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
1
Flash point Non-flammable
Related compounds
Other anions
Lanthanum(III) chloride
Other cations
Cerium(III) hydroxide
Actinium(III) hydroxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis

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Lanthanum hydroxide can be obtained by adding an alkali such as ammonia to aqueous solutions of lanthanum salts such as lanthanum nitrate. This produces a gel-like precipitate that can then be dried in air.[2]

La(NO3)3 + 3 NH4OH → La(OH)3 + 3 NH4NO3

Alternatively, it can be produced by hydration reaction (addition of water) to lanthanum oxide.[3]

La2O3 + 3 H2O → 2 La(OH)3

Characteristics

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Lanthanum hydroxide does not react much with alkaline substances, however is slightly soluble in acidic solution.[2] In temperatures above 330 °C it decomposes into lanthanum oxide hydroxide (LaOOH), which upon further heating decomposes into lanthanum oxide (La2O3):[4]

La(OH)3   LaOOH
2 LaOOH   La2O3

Lanthanum hydroxide crystallizes in the hexagonal crystal system. Each lanthanum ion in the crystal structure is surrounded by nine hydroxide ions in a tricapped trigonal prism.[5]

References

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  1. ^ "C&L Inventory". echa.europa.eu.
  2. ^ a b E.V. Shkolnikov (2009). "Thermodynamic Characterization of the Amphoterism of Hydroxides and Oxides of Scandium Subgroup Elements in Aqueous Media". Russian Journal of Applied Chemistry. 82 (2): 2098–2104. doi:10.1134/S1070427209120040. S2CID 93220420.
  3. ^ Ding, Jiawen; Wu, Yanli; Sun, Weili; Li, Yongxiu (2006). "Preparation of La(OH)3 and La2O3 with Rod Morphology by Simple Hydration of La2O3". Journal of Rare Earths. 24 (4): 440–442. doi:10.1016/S1002-0721(06)60139-7.
  4. ^ Michael E. Brown, Patrick Kent Gallagher (2008). Handbook of Thermal Analysis and Calorimetry. Elsevier. p. 482. ISBN 978-0-44453123-0.
  5. ^ Beall, G.W.; Milligan, W.O.; Wolcott, Herbert A. (1977). "Structural trends in the lanthanide trihydroxides". Journal of Inorganic and Nuclear Chemistry. 39 (1): 65–70. doi:10.1016/0022-1902(77)80434-X.
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